... maintenance 5.ISO9001-2008:SGS Chain Grate Hot Air FurnaceHigh heat transfer efficiency with an overall efficiency of no less than 75 ... % Highly mechanized, stable running, and convenient operation Adaptable for various coals with heat generation value of no less than 4,500Kcal ... , feedstuffs, chemicals, building materials, minerals, and more Chain Grate Hot Air Furnace with high efficiency